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Infinity runs well past humidity set point

My target humidity is 52. All of a sudden the system starts running on first stage cool bringing it down to 48 and then finally stopped. My set point temp was 77 and it was at 77 all along. What is that made the system run past the humidity set point? Maybe there's something I am missing here.

Air conditioners are horribly inefficient for the first few minute after they start up, so the best control systems do their best to maintain comfort while running long cycles (ie 30 minutes off, 30 minutes on is far more efficient than an hour of 5 on, 5 off). Humidity isn't quite as tightly controllable as temperature, though, without making a big sacrifice in efficiency.

Despite the whole degrees the Infinity system shows on the display, it regulates the temperature far more tightly than that. Thanks to rounding, what you just saw may have cooled the house from 77.4 to 76.6. As part of that same cooling cycle, the system also reduced the humidity (as any AC system will do). The system is not intended to avoid getting drier than the humidity setpoint during cooling season, just to make sure that it doesn't get much wetter than that. My condo with an Infinity system frequently runs 42% humidity during the height of summer, even with a setpoint of 48%. On the other hand, if you need dehumidification without cooling, it may let the humidity go as much as 6% over the setpoint before it starts up to dry things out. On the whole, though, it will average out to your setpoint (or better).

Temperature and humidity are related by vary fairly independently, too. It may be that the system knew that it wouldn't need another cooling cycle for at least an hour, but that your humidity would climb unacceptably during that time. In that case, it might intentionally go a bit beyond the RH setpoint to avoid needing to run a short cycle when it could wait and run a longer cycle awhile later.

The logic behind it all is the stuff that keeps engineers up at night. Don't worry about it, it sounds quite normal.

Originally posted by wyounger Air conditioners are horribly inefficient for the first few minute after they start up, so the best control systems do their best to maintain comfort while running long cycles (ie 30 minutes off, 30 minutes on is far more efficient than an hour of 5 on, 5 off). Humidity isn't quite as tightly controllable as temperature, though, without making a big sacrifice in efficiency.

Despite the whole degrees the Infinity system shows on the display, it regulates the temperature far more tightly than that. Thanks to rounding, what you just saw may have cooled the house from 77.4 to 76.6. As part of that same cooling cycle, the system also reduced the humidity (as any AC system will do). The system is not intended to avoid getting drier than the humidity setpoint during cooling season, just to make sure that it doesn't get much wetter than that. My condo with an Infinity system frequently runs 42% humidity during the height of summer, even with a setpoint of 48%. On the other hand, if you need dehumidification without cooling, it may let the humidity go as much as 6% over the setpoint before it starts up to dry things out. On the whole, though, it will average out to your setpoint (or better).

Temperature and humidity are related by vary fairly independently, too. It may be that the system knew that it wouldn't need another cooling cycle for at least an hour, but that your humidity would climb unacceptably during that time. In that case, it might intentionally go a bit beyond the RH setpoint to avoid needing to run a short cycle when it could wait and run a longer cycle awhile later.

The logic behind it all is the stuff that keeps engineers up at night. Don't worry about it, it sounds quite normal.

Thanks! Why didn't they state all that in the skimpy manual. Say, BTW, do you know how to get the fan speed and static pressure ? What button do you press??